1. Field of the Invention
Exemplary aspects of the present invention generally relate to a process unit and an image forming apparatus including the process unit.
2. Description of the Background
Related-art image forming apparatuses, such as copiers, printers, facsimile machines, and multifunction devices having two or more of copying, printing, and facsimile functions, typically form a toner image on a recording medium (e.g., a sheet of paper, etc.) according to image data using an electrophotographic method. In such a method, for example, a charger charges a surface of an image carrier (e.g., a photoconductor); an irradiating device emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a developing device develops the electrostatic latent image with a developer (e.g., toner) to form a toner image on the photoconductor; a transfer device transfers the toner image formed on the photoconductor onto a sheet of recording media; a cleaning device removes residual toner from the surface of the photoconductor, and a fixing device applies heat and pressure to the sheet bearing the toner image to fix the toner image onto the sheet. The sheet bearing the fixed toner image is then discharged from the image forming apparatus.
There is known a process unit including the photoconductor and at least one of the charger, the developing device, the cleaning device, and so forth. The process unit is detachably attachable to the image forming apparatus, and can be replaced with a new process unit upon repair or at the end of the product life thereof so that the image forming apparatus itself can be continuously used thereafter. Thus, the image forming apparatus can be returned to service merely by replacing the process unit with the new process unit, thereby improving work efficiency. Further, on occasion even a user may easily replace the process unit with the new process unit.
The image forming apparatus employing the process unit is generally provided with a waste toner container that stores waste toner, that is, the residual toner removed from the photoconductor by the cleaning device after image formation is completed. A cycle of replacement of the waste toner container filled up with the waste toner is generally shorter than the product lives of the other components such as the photoconductor and the developing device. Therefore, only the waste toner container is replaced with a new waste toner container, and the process unit itself is continuously used thereafter without replacement until the end of the product life thereof.
In addition, the process unit is often provided with a lubricant supplier that supplies a lubricant to the surface of the photoconductor in order to more effectively clean the surface of the photoconductor, thereby preventing white spots in a resultant image caused by incomplete transfer of the toner image onto the sheet. However, in a case in which the process unit is provided integrally with the lubricant, the process unit as a whole needs to be replaced with the new process unit upon exhaustion of the lubricant even when the other components such as the photoconductor, the charger, and the developing device are still serviceable, resulting in a cost increase and a waste of resources. In order to use the process unit until the actual end of its product life, a process unit having a configuration in which the lubricant alone is replaceable has been proposed.
In recent years, compact image forming apparatuses often include a waste toner container to which waste toner is directly discharged from a process unit, thereby reducing a size, number of components, and production costs of the image forming apparatus. In such image forming apparatuses, the process unit and the waste toner container are provided close to each other, to limit a size of the waste toner container and shorten a cycle of replacement of the waste toner container. As a result, the cycle of replacement of the waste toner container may approach the cycle of replacement of the lubricant. However, the waste toner container and the lubricant are individually replaced with a new waste toner container and a new lubricant at separate times. Consequently, work efficiency is degraded when replacement of the waste toner container and the lubricant are needed one after another.